Breather valve



- Y 1,6 7,4 Aug. 2, 1927. J KUHL I 3 89 BREATHER VALVE Filed Nov. 25, 1924 '7 at?! IIII j 5,

Fl 8. 8. i? I gnmnto'p )7 t )8 JOHN KUH L.

. I v I Patented Aug. 2, 1927.

UNITED STATES PATENT OFFICE.

JOHN KUHL, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO STANDARD OIL COMPANY OF CALIFORNIA, OF SAN FRANCISCO, CALIFORNIA,

A CORPORATION OF DELAWARE.

BREATHER VALVE.

Application filed November 25, 1924. Serial No. 752,276.

This invention relates to breather valves and is more particularly directed to pressure and vacuum relief valves for use in connec tion with containers of volatile fluids.

The use in recent years of gas-tight sealed roofs on oil tanks has introduced a particular problem in the manner of providing such tanks with a safe and sure means of venting. The vapor or gas in the tank between the liquid surface and the roof expands and contracts with temperature variations and the volume of vapor or gas varies with the rise and fall of the liquid surface as the volume of the oil in the tank is changed. The nature ofthe ordinary tank construction is'not such as to withstand the pressure developed by this expansion or contraction without provisions for allowing escape and intake of gas or'air through the roof. This venting could be accomplished by means of an open hole in the roof but this method defeats, in a measure, the purpose of the gas-tight tank construction, namely, reduction of the vapor loss and fire hazard.

It is, therefore, necessary to provide a pressure and vacuum relief valve to be placed on such a gas-tight roof and such a valve must be sensitive to slight pressure change for the gas pressure which a tank roof can safely stand is very slight. It must be susceptible to accurate regulation for some conditions demand that it shall not function until a certain pressure is reached. Safety requires that its operation be certain for failure to operate might result in serious damage and be very costly.

The operation of most commercial pressure valves is such that a comparatively small increase in the quantity of gas to be handled by the valve results in a considerable increase in the pressure required to operate such a valve. It has been found in practice that with the use of pressure valves as now constructed sudden. temperature changes or suddenvariations in a pumping rate may make it necessary for the valve on the tank to handle large quantitiesof gas in a short space of time and as the design of I these valves are such that a material increase in pressure is-neoessary to force these quantities of gas through the valve, and dangerous pressures are developed within the tank.

An object of this invention is to provide a means to automatically relieve pressure or or vacuum has been reached within the container.

An object of this invention is to provide a pressure and vacuum relief valve to be placed on the roof of a tank or container that has a relatively large relief capacity without materially increasing the pressure or vacuum on the container.

An object of this invention is to provide a pressure and relief valve having a liquid seal and being so designed as to prevent the valve from chattering.

Other objects and advantages of this in I vention will be apparent from the following detailed description of a preferred embodiment thereof as illustrated in the accompanying drawings:

In the drawings:

Figure l is a diagrammatic side elevation of a vapor line tank illustrating an embodiment of this invention.

Fig. 2 is a top plan view partly in section of a breather valve embodying this invention. Fig. 3 is a side elevation thereof partly in section.

Fig. at is a sectional side elevation of one of the pressure relief valves embodied in this invention.

Fig. 5 is a sectional view taken substantially on the line 55 of Fig. 4.

Fig. 6 is an enlarged fragmental sectional side elevation illustrating a manner of taching the hood to the body.

Fig. 7 is a sectional end elevation taken substantially on the line -7-'7 of Fig. 6.

Fig. 8 is a side elevation partly in section illustrating the cage and cylindrical screen flash arrest-er embodied in this invention.

In the embodiment of this invention illus trated in the accompanying drawings, 1 indi-' cates the main ,bodyof a pressure valve and the flash arrester.

bottom for a pipe connection to a fluid tank or other system to which the valve is to be connected, the said body 1 having tapered openings 3 in the bottom for holding seats 4 of vacuum relief valves 5, and making a gas-tight connection between the main body and valve seat, and also having tapered opening 6 for holding the seat 4 of the pres:

'- and may be securely held so engaged with the said body by means of the member cast to theoutside of'the hood 9 having slots 31 adapted to register with the slots cut in the hood.

The members 30 have radially extending recesses 32 adapted to engage the edge of Washers 33fitted to the bosses 10. B means of such a provision it is'imposvsi 1e to remove the hood 9 from the body 1 4 without unscrewing the wing nuts 11 and disengaging the washers 33 from engagement with the radial recesses 32. A boss 12 onthe side of the body 1 is adapted to receive a pressure auge connection. The cylindrical screen ash arrester 8 is for the protection from outside fire of the tank or other system to which the valve is to'be connected and consists of a cylindrical cage 13'of a material having a high thermal conductivity closed at the topas indicated at 14 and open at the bottom. This cage 13 has slots 15, and a handle 16 on the to for easy removal from the main body 1. K screen 17 of fine mesh and a material having high thermal conductivity is wrapped around the outside of thecage 13 and securely fastened thereto 1 by meansof wire 18 and a brass strap ,or-the same may be fastened to the cage 13 by any other suitable means. The purposes for use of such a cage 13 are to keep the screen 17 cool in case of fire by takin the heat away from the screen to the main ody 1, and as a convenient support for the screen 17 and as a convenient means for handling the flash arrester and at the same time insuring a tight joint between the main body and the flash arrester.

' The valves darepreferably ofsimilar construction and are employed in one instance for a vacuum relief valve and in the other instance for the pressure relief valve. These valves serve to relieve the pressure in the tank whenever the pressure reaches a.predetermined amount. They can be designed to open at very slight pressures and they have a large relieving capacity without materially increasing thepressure or vacuum in the tank. They have the advantage. of being tightly closed and are not likely to stick.

'Therefore, the operation of these valves is very reliable.

The valves 5 comprise a cast seat 4 having a groove 20 for holding mercury or similar fluid serving as a seal and having a rib 21 with a cylindrical bore 22 which serves as a guide for the valve stem 23. The outside of the valve seat 4 is tapered to fit the openings 3 and 6 .in the main body 1. The rib 21 is tapped to receive cap screws 24 for holding a dash pot 25. to the valve seat 4. The valve head is formed of a light metal disc 26 which seats into the mercury groove 20. To the center of the disc is secured a valve stem which valve stem 23 is preferably in the nature of a hollow tube. To the lower end of the valve stem 23 are attached two wide cylindrical washers 27 between which a guide plate 28 is held. The dash pot 25 is preferably filled with oil so that the valve stem 23, the washers 27 and the disc plate 28 are immersed in oil. A stop pin 29 passing through the valve stem 23 limits the opening of the valve disc 26 by coming in contact with the lower edge of the bore 22 through which the valve stem 23 passes. as the lower guide for the valve stems 23 of the valves 5 and principally prevents the valve from chattering and thereby prevents the blowing out of mercury and in general insures smooth operation when the. valve is opening or closing. The opening pressure on the valve is determined only by the weight of the head 26 together with the weight of the stem 23 and its parts and is not dependent upon the depth of the seal formed in the mercury.

In Fig. 1 is shown the manner in which these breather valves may be used in connection with an oil tank vapor line, whichvapor line is the subject of the co-pending application of John M. Evans, filed November 20, 1924, Serial No. 7 51,103, where two of such breather valves are shown connected to the top of tanks A and B, which tanks A and B are'connected by means of a vapor line C in sucha manner that the excess vapor pressure developed above the surface of the oil in the tank A' during the filling of the tank A, may be conveyed through the line C to a tank B which is being emptied.

A third breather valve is illustrated as positioned in the vapor line'O. The operation of this breather valve is that when excess pressure is developed within the container to which the valve is attached, the gas or vapor causing the pressure flows upward through the connection to the central opening 7 of the body 1 of the pressure valve and at a predetermined pressure raises the pres sure relief valves 5, two of which are shown in the breather valve illustrated in the accompanying drawings, however, it being un- This dash pot arrangement serves- "derstood that any suitable number of such valves 5 are reseated and the tank main-' tained closed. In the case of a drop in temperature of the oil in the tank or in theease of withdrawal of the oi} fromthe tank'or container, a vacuum or reduced pressure is produced therein, which reduced pressure is transmitted upward into the breather valve and at a predeterminedpressure causes the vacuum relief. valves 5 to open and allow air or other suitable gas to flow intoihe tank and relieve the said vacuum. Having fully described the preferred embodiment of this invention, it is to'be understood that it is not intended 'tolimit this invention to the exact-(preferred .des cri tion herein disclosed, which ma obvious y be varied within claim.

I claim:

- A breather valve comprising a body hav' 'ing a hood loosely adapted to fit the body and being spaced therefrom, pressure and a the spirit o the '.appended.

vacuum relief valves secured within the 7 body, .a flash arrester, meansifor connecting thesaid body to acontainer, and a chamber, surrounded by the flash arrester through which the pressure or vacuum is transmitted to the said relief valves.

Signed at- San Francisco, California, this 3rd day of November, 1924.

JOHN KUHL. 

